1. Field of the Invention
The present invention relates to an electric shaver.
2. Prior Art
As seen from FIG. 8 that shows a prior art electric shaver 50, shaving debris 52 produced by shaving is collected in a space inside the shaver 50. This space is surrounded by the upper surface 56a of a shaver body 56 from which the inner cutter 54 protrudes, an outer cutter frame 58 which is attached, in a detachable manner, to the shaver body 56 so as to cover the upper surface 56a, and an outer cutter 60 which is mounted to the outer cutter frame 58. For the most part, such shaving debris falls and accumulates on the upper surface 56a of the shaver body 56. Thus, the upper surface 56a of the shaver body 56 functions as a shaving debris receiving part, and this is true for both rotary type electric shavers and reciprocating electric shavers.
The shaving debris 52 accumulated on the upper surface 56a of the shaver body 56 must be cleaned away. However, since the upper surface 56a is hidden by the outer cutter frame 58 and outer cutter 60, it cannot be seen from the outside. As a result, the proper time for performing the cleaning may be missed, and shaving debris 52 would spill out from the outer cutter 60 during shaving. If shaving debris 52 is allowed to accumulate "as is", the cutting capability of the electric shaver drops, and the time required for a single use of the electric shaver increases, resulting in that a driving current for the motor is excessively consumed and the battery consumption accelerates. Furthermore, if shaving debris 52 is allowed to accumulate, various problems occur such as an unpleasant odor, poor hygiene, etc. Accordingly, the periodic cleaning of shaving debris 52 is indispensable for effective and comfortable use of an electric shaver.
In recent years, a new electric shaver has been developed. In this electric shaver, the shaving debris accumulated on the shaving debris receiving part is detected; based upon such a detection, an indication that it is time to clean the shaver is shown on a display 62 of an LED (light-emitting diode) or LCD (liquid crystal display), etc. which is disposed on the shaver body 56 of the electric shaver.
In this electric shaver, the shaving debris is detected by the process as shown in FIG. 9: the use time of the motor 64 which drives the inner cutter 54 (e. g., the time for which the power supply switch 66 is switched on) is counted by an MPU (microprocessor) 68 so as to produce a counted value; when this counted value reaches a preset value, it is judged that the proper cleaning time has arrived; and the fact that the proper cleaning time has arrived is shown on the display 62 so that the user is informed of the time to clean up the shaving debris. This is disclosed in, for instance, Japanese Patent Application Laid-Open (Kokai) No. H1-83289. In other words, the system above utilizes the fact that the accumulation of shaving debris increases as the use time of the electric shaver increases, or as the use time (operating time) of the motor or the ON time of the power supply switch 66 increases.
When the accumulated shaving debris has been cleaned away, it is necessary to perform a new count from the initial value (ordinarily zero); and it is generally true that the outer cutter frame 58 is always removed when the shaving debris 52 is cleaned away. Accordingly, based upon these facts, the shaver is provided with a detecting means 70 for detecting the removal of the outer cutter frame 58 (in which, for example, a detection switch 70 is installed in the attachment position of the outer cutter frame 58 of the shaver body 56), and the MPU 68, that judges that the shaving debris 52 has been cleaned away whenever the outer cutter frame 58 is removed, resets the counted value, thus returning the counted value to the initial (zero) value.
However, some users remove the outer cutter frame 58 before the display 62 indicates that the cleaning time has come so as to look inside the shaver and then just put back the outer cutter frame 58 on the shaver body without cleaning away the shaving debris. There may also be users who remove the outer cutter frame 58 in order to perform cleaning as a result of the indication of the cleaning time shown on the display 62 but re-attach the outer cutter frame 58 without cleaning away the shaving debris because of distractions by some other matter.
In these situations, since the outer cutter frame 58 is removed, the counted value which serves as the basis for judging that the proper cleaning time has arrived returns to the initial value; and as a result, since the users did not remove the shaving debris, a discrepancy subsequently occurs between the accumulation of shaving debris and the display timing with which the display 62 indicates the proper time for cleaning. Thus, even though the shaving debris accumulates beyond the amount at which cleaning is required, the display 62 still does not indicate that it is time for cleaning until the counted value again reaches the preset reference value. Accordingly, the proper time for cleaning is not accurately indicated on the display 62.